Problem 4 - Campbell Biology Concepts & Connections

Question

Natural selection is sometimes described as "survival of the fittest." Which of the following best measures an organism's fitmess? a. how many fertile offspring it produces b. how strong it is when pitted against others of its species C. its ability to withstand environmental extremes d. how much food it is able to make or obtain

Step-by-Step Solution

Answer

a. how many fertile offspring it produces

Step 1 - Understanding 'Fitness'

Fitness in biology is defined by an organism's ability to survive and reproduce fertile offspring in its environment. It is an indicator of how well an organism is adapted to its surroundings.

Step 2 - Analyzing Each Option

Review each option to determine which best measures fitness: a. Number of fertile offspring b. Strength against others of its species c. Ability to withstand environmental extremes d. Amount of food obtained or produced

Step 3 - Focusing on Reproduction

Reproduction is the key to passing on genes. Therefore, option a, which measures the number of fertile offspring, directly quantifies fitness.

Step 4 - Elimination Process

Eliminate the other options because: b. Strength does not directly measure reproductive success. c. Withstanding extremes is important but not the best measure of fitness. d. Obtaining food is essential for survival but not the sole measure of reproductive success.

Key Concepts

Biological Fitness

Biological fitness is a key concept in understanding natural selection. It refers to an organism's ability to survive, reproduce, and pass on its genes to the next generation.
Fitness is measured by the number of fertile offspring an organism produces. It's not just about being the strongest or the most resilient. These traits are important, but they are beneficial only if they contribute to reproduction.
In simple terms, fitness in biology is all about passing on one's genes. The more descendants an organism has, the higher its biological fitness.

Reproductive Success

Reproductive success is a critical component of an organism's fitness. It determines how well an organism's genetic material is represented in future generations.
This concept is directly tied to biological fitness. The focus is on producing fertile offspring that can themselves reproduce.

• Organisms with high reproductive success leave more offspring.
• Their genetic traits become more common in the population over time.

Reproductive success ensures that advantageous traits, those that help in survival and reproduction, are passed on and become predominant in the gene pool.

Adaptation

Adaptation refers to the process through which organisms become better suited to their environment. It's a result of natural selection acting on heritable traits.
Organisms with traits that enhance their survival and reproductive success are more likely to pass these traits on to the next generation.

• Adaptations can be physical, like a bird's beak shape suited for its food source.
• They can also be behavioral, like migratory patterns to avoid harsh climates.

Adaptations improve an organism's biological fitness by enhancing its ability to survive and reproduce within its environment.